(a) Field of the Invention
The present invention relates to a carrier conveying mechanism for electrophoretic apparatus which also serves as a support to be used in the step of applying samples onto said carrier.
(b) Description of the Prior Art
The electrophoresis comprises a step to apply a sample such as serum onto a carrier made of cellulose acetate or the like material, a step to electrically energize said carrier to form fractionated patters thereon, a step to color and discolor the carrier and a step of photometry. An automatic electrophoretic apparatus for carrying out these steps automatically and continuously requires a mechanism for conveying the carrier from a step to the next step. As an example of such conveying mechanism, there can be mentioned a travelling belt which conveys a carrier while mounting it on said belt. When a conveying mechanism equipped with such a belt is used with a sample applicator, operation of the conveying mechanism is stopped in the course of carrier conveyance to apply a sample onto the carrier. Speaking more concretely, operation of the conveying mechanism is stopped when the carrier reaches a predetermined position, and a sample applicator is lowered down onto the carrier and a sample is applied onto the carrier while it is mounted on the belt. In such a case, however, the sample cannot be applied adequately if the belt is kept in contact with the the carrier at the portion onto which the sample is to be applied. Further, the sample applied onto the carrier may be brought into frictional contact with the belt when the conveying mechanism is operated once again after the sample application. Therefore, the conveying mechanism uses two belts arranged at a definite interval so that they will not brought into contact with the carrier at the portions at which the sample is to be applied. In case of such a conveying mechanism, however, the carrier is flexed when the tip of the sample applicator is brought into contact with the carrier for applying a sample thereto. Such flexture is undesirable for sample applying operations. If the carrier is conveyed while it is sagged between the conveying belts, there is caused a defect that the carrier cannot be conveyed securely.
As conveying mechanisms which have corrected the above-mentioned defect, there have already known the one disclosed by Japanese published examined patent application No. 46480/78, U.S. Pat. No. 4,070,986, etc. Partial outline of this conveying mechanism is shown in FIG. 3. Speaking concretely, passed around two rollers 11 (though only one roller is shown in the drawing, two front and rear rollers are arranged) are two belts 12 and 13 on which a carrier is mounted so as to be conveyed with travelling of the belts. The reference numeral 14 represents a support arranged between the two belts and having a cavity 14a formed at the top center thereof. This support is normally placed at the position shown in the drawing and therefore causes no hindrance to conveyance of the carrier 9 with the belts 12 and 13. In case of such a conveying mechanism, the carrier 9 is conveyed as the belts 12 and 13 travels, and the conveying mechanism stops operating to make the carrier stationary when the carrier reaches the position at which a sample is to be applied thereto. At this position, a sample applicator 10 goes down and the support 14 goes up. Before the tip of the blade 10a of the sample applicator 10 is brought into contact with the carrier, however, the tip of the support 14 reaches the height of the belt, i.e., the level shown in the chain line in FIG. 3, and is stopped at this position. When the tip of the sample applicator presses the carrier 9 to apply a sample adhering to the blade 10a onto the carrier, the carrier cannot be flexed since the support is kept in contact with the bottom surface of the carrier. Further, owing to the cavity 14a formed on the top of the support 14, the portion of the carrier to which a sample is applied is not kept in contact with anything. After the sample has been applied onto the carrier, the sample applicator goes up and the support 14 goes down so that the support 14 is kept in the position shown in FIG. 3 when the conveying mechanism operates and the carrier is conveyed once again. The conventional conveying mechanism described above requires the support and, in addition, an interlocking mechanism which operates the support in conjunction with the motion of the sample applicator, thereby being very complicated in its construction. Moreover, since the top surface of the support must be in parallel with the belts when the former is raised to its upper position, the mechanism has a defect to require tedious adjustment and so on.